Pattern transition, microstructure, and dynamics in a two-dimensional vibrofluidized granular bed

Ansari, Istafaul H.; Alam, Meheboob

dc.contributor.author	Ansari, Istafaul H.
dc.contributor.author	Alam, Meheboob
dc.date.accessioned	2017-01-24T06:26:35Z
dc.date.available	2017-01-24T06:26:35Z
dc.date.issued	2016
dc.identifier.citation	Ansari, I. H.; Alam, M., Pattern transition, microstructure, and dynamics in a two-dimensional vibrofluidized granular bed. Physical Review E 2016, 93 (5), 17 http://dx.doi.org/10.1103/PhysRevE.93.052901	en_US
dc.identifier.citation	Physical Review E	en_US
dc.identifier.citation	93	en_US
dc.identifier.issn	Experiments are conducted in a two-dimensional monolayer vibrofluidized bed of glass beads, with a goal to understand the transition scenario and the underlying microstructure and dynamics in different patterned states. At small shaking accelerations (Gamma = A omega(2)/g < 1, where A and omega = 2 pi f are the amplitude and angular frequency of shaking and g is the gravitational acceleration), the particles remain attached to the base of the vibrating container; this is known as the solid bed (SB). With increasing Gamma (at large enough shaking amplitude A/d) and/or with increasing A/d (at large enough Gamma), the sequence of transitions/bifurcations unfolds as follows: SB ("solid bed") to BB ("bouncing bed") to LS ("Leidenfrost state") to "2-roll convection" to "1-roll convection" and finally to a gas-like state. For a given length of the container, the coarsening of multiple convection rolls leading to the genesis of a "single-roll" structure (dubbed the multiroll transition) and its subsequent transition to a granular gas are two findings of this work. We show that the critical shaking intensity (Gamma(LS)(BB)) for the BB -> LS transition has a power-law dependence on the particle loading (F = h(0)/d, where h(0) is the number of particle layers at rest and d is the particle diameter) and the shaking amplitude (A/d). The characteristics of BB and LS states are studied by calculating (i) the coarse-grained density and temperature profiles and (ii) the pair correlation function. It is shown that while the contact network of particles in the BB state represents a hexagonal-packed structure, the contact network within the "floating cluster" of the LS resembles a liquid-like state. An unsteadiness of the Leidenfrost state has been uncovered wherein the interface (between the floating cluster and the dilute collisional layer underneath) and the top of the bed are found to oscillate sinusoidally, with the oscillation frequency closely matching the frequency of external shaking. Therefore, the granular Leidenfrost state is a period-1 wave as is the case for the BB state.
dc.identifier.uri	https://libjncir.jncasr.ac.in/xmlui/10572/2158
dc.description	http://dx.doi.org/10.1103/PhysRevE.93.052901	en_US
dc.description.abstract	@American Physical Society, 2016	en_US
dc.description.uri	2470-0045	en_US
dc.description.uri	2470-0053	en_US
dc.language.iso	5	en_US
dc.publisher	English	en_US
dc.rights	American Physical Society	en_US
dc.subject	Physics	en_US
dc.subject	Plane Couette-Flow	en_US
dc.subject	Nonlinear Stability	en_US
dc.subject	Convection Cells	en_US
dc.subject	Vibrating Beds	en_US
dc.subject	Fluidization	en_US
dc.subject	Behavior	en_US
dc.subject	Bifurcation	en_US
dc.subject	Instability	en_US
dc.subject	Simulation	en_US
dc.subject	Separation	en_US
dc.title	Pattern transition, microstructure, and dynamics in a two-dimensional vibrofluidized granular bed	en_US
dc.type	Article	en_US